It is difficult to overestimate the role of safety valves in the heating system, because the performance and reliability of engineering systems depend on their proper operation, settings and quality. Relief valves, as their name suggests, prevent the system from being overpressured.
The heat carrier in a vicious circle from heating increases in volume, and the increase in volume should be in the expansion tank, while the pressure in the heating circuit also increases. During normal operation of the system, the safety valves should be in the closed position, only in case of incorrect settings or incorrect selection of the expansion tank, when it does not include an excess volume of coolant and the pressure rises above the maximum allowable level, the valve should work.
Safety valves are installed in systems with closed circuits in which the heat carrier is heated: these are systems with a solar collector and thermalpumps; closed systems with hot water supply, which are connected to heating networks; as well as those connected through heat exchangers or autonomous boilers.
When selecting a valve, it is necessary to study the characteristics of each element of the heating system. It is selected in such a way that the pressure for its operation is no more than the maximum working pressure of a less durable heating element. In addition, the trigger pressure must be in the middle of all adjustable values. Relief valves have an outlet, most often one or two sizes larger than the inlet.
In systems with expensive equipment or with an increased risk of pressure increase, it is recommended to install two valves located side by side. In addition to systems with hydraulic closed circuits, valves can be used in any application in which the pressure is capable of exceeding the maximum allowable value. These can be systems that are connected to the heating network according to a dependent scheme, in the hydraulic operation of which the possibility of emergency situations with an increase in pressure above the maximum values \u200b\u200bis not excluded.
In this case, safety valves are installed in the return pipeline and selected so that the flow rate of the discharged coolant is greater than the flow rate that enters the heating system in emergency mode.
By design, valves are divided into diaphragm and spring valves.
The inner surface of the diaphragm valve, as well as the sealing surfaceconnecting flange are covered with protective materials resistant to various aggressive chemicals. Thanks to him, the working parts are isolated from the external environment. The guides ensure the correct movement of the spool, which compresses the membrane.
The safety spring valve can be used for various operating pressure settings due to the configuration with various springs. Also, many valves are available with a special mechanism (mushroom, lever) for control purge.
